Charging device for charging and emptying the heating chamber of vacuum quenching furnaces

ABSTRACT

A charging device for a furnace which has a housing with a charging opening and an oil quenching chamber and a heating chamber. The charging device has a vertically moveable carriage with a support thereon moveable horizontally to convey charges from said opening across said oil quenching chamber to said heating chamber and back. Chains drive the carriage vertically and the support horizontally and the chains for the support disengages therefrom when the support is over the body of oil in the oil quenching chamber to permit the support and carriage to be moved vertically to treat a charge in the coil.

1451 Apr. 2, 1974 United States Patent Limque et al.

PATENED APR 2 1974 SHtU l Uf 4 The present invention concerns a charging device for charging and emptying the heating chamber of a vacuum quenching furnace with an oil quenching chamber arranged ahead of the heating chamber, while the oil bath is .located below the transporting path for the charges to be transported through the oil quenching chamber into the heating chamber.

A charging device for charging and emptying the heating chamber of a vacuum quenching furnace with an oil quenching chamber is known according to which a cantilever transports the respective charge in a basket in a horizontal direction from the oil quenching chamber into the heating chamber and back. To this end, the cantilever is arranged on a carriage which is equipped with a lifting device and which is movable on two stationary rails in the oil quenching chamber. The lifting device on the carriage is intended to be able to change the cantilever to a slight degree as to height so that the charging baskets can be lifted off from a stationary support in the heating chamber and can be lowered onto this stationary support. For purposes of lowering the hot charges into the oil bath of the oil quenching chamber, the latter is provided with a lifting table upon which the charging basket are deposited by means of the cantilever after they have been taken out of the heating chamber, the lifting table being adapted subsequently to lower the charging baskets into the oil bath.

With this heretofore known charging device, all movements are effected by hydro-pneumatic lifting elements which are controlled by limit switches hit directly. lnasmuch as all units are located in an evacuated chamber and during the working process are exposed not only to high temperatures but also to the-oil vapors of the oil bath, they are relatively easily liable to disorders. If any sealing sleeves or flexible feeding lines of the hydraulic system are damaged, the leakage of the hydraulic oil will bring about a soiling of the specific hardening oil. A further drawback of the heretofore known charging device consists in that due to the transfer of the hot charges from the cantilever onto the lifting table delays occur which harmfully affect the quality of the hardened goods.

It is, therefore, an object of the present invention to provide a charging device for charging and emptying the heating chamber of a vacuum quenching furnace of the above described type which, while employing simple mechanical structural elements, will require relatively little space and will assure a trouble-free transporting of the charging baskets into the heating chamber as well as into the oil bath without the necessity of a transfer and without delays inherent thereto while the drive and the control of the charging device will be provided outside the furnace.

This object and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawings, in which:

FIG. 1 represents a diagrammatic longitudinal section through a vacuum quenching furnace according to the invention.

FIG. 2 represents a cross section through the oil quenching chamber, said section being taken along the line II II of FIG. l.

FIG. 3 is a side view of the charging device according v to the invention with the supporting means moved into the heating chamber. t

FIG. 4 represents a side view similar-to that of FIG. 3 with the supporting means being located in the oil quenching chamber.

FIG. 5 is a further side view of the charging device according to the invention showing the supporting means lowered into the oil bath. y

FIG. 6 is a side view of the driving device for the cantilever of the charging device illustrated on a larger scale than that of FIGS. 1 to 5.

The above outlined objects have been realized according to the invention by having the cantilever consist of a supporting member for the charging basket and a base member on which the supporting member is horizontally displaceably mounted. The base member in its turn is displaceable on a horizontal bracket or cantilever of a lifting carriage which latter is mounted in the oil quenching chamber so as to be vertically movable on guiding rails.

According to a further feature of the invention, the lifting carriage as well as the supporting `member of the cantilever are respectively adapted to be driven by two lateral chains which pass over sprocket wheels in vertical and horizontal direction, the sprocket wheels being respectively journalled in the oil quenching chamber. The chains are connected to the lifting carriage and the supporting member respectively and are adapted in pairs to be driven by a motor which is located outside the quenching furnace. The drive of the chains which to the lifting carriage, the horizontally extending chains are connected to the supporting member so as to be disengageable in the front position of the supporting member. According to a further feature of the invention, the horizontally extending chains are to this end interconnected by a pivotable shaft having laterally connected thereto two arms and two guiding rollers which by means of stationary control cams bring about such a pivot movement of the arms, which may be termed catching arms, that the arms are adapted to be lifted out of catching hooks on the supporting member or are adapted to be introduced into such hooks. According to a preferred embodiment of the invention, the chains are vby additional sprocket wheels in the front portion of the oil quenching chamber passed over a vertically extending path in the range of which there are provided the control cams for the lifting of the arms out of and introducing of the arms into the catching hooks.

Referring now to the drawings in detail, the funda-l mental construction of the vacuum quenching furnace according to the invention is best shown in FIG. l. The vacuum quenching furnace has a heating chamber 1 and an oil quenching chamber 2 which are arranged-in a pressure container 3a and 3b respectively, the pressure container 3b resting on the oil container 4 for the oil quenching chamber 2. While the pressure container 3a housing the heating chamber 1 is closed by a firm container bottom 5, the pressure container 3b for the oil quenching chamber '2 has a front door 6 which is adapted to be opened and which at the same time serves for charging and emptying the quenching furnace.

Between the chamber 1 and the oil quenching chamber 2 there is provided a charging valve of which FIG. 1 shows the valve wall 7 and valve door 8. The valve door 8 is actuated by'a lifting cylinder 9. For a clearer illustration, the units for producing the vacuum as well as the vacuum conduits are not shown in the drawings.

The heating chamber 1 consists of a parallelepipedshaped insulating housing 11 which has that end lface thereof which faces toward the oil quenching chamber 2 provided with a heating chamber door 12 which is movable in upward direction, the door 12 being operable by a lifting device 13. In the insulating housing 1l there is provided a plurality of heating elements 14 which are preferably heated electrically. By means of these heating elements 14, the charge in the charging basket is heated. The charging basket 10 is to Athis end deposited upon a supporting frame 15 extending into the heating chamber 1.`

For charging andemptying the quenching furnace there is provided a movable loading device which is not shown in the drawings and which is similar to a fork lifting truck which conveys the charging basket 19 into the oil quenching-chamber 2 or withdraws the same therefrom. The transporting of the charging basket 10 within the vacuum quenching furnace is effected by means of a charging device which is illustrated in detail in three different Vpositions in FIGS` 3 to 5 respectively.

This charging device has two vertical parallel guiding rails 16 which in the vicinity of the valve 7 are firmly arranged in the oil quenching chamber 2. A lifting carriage l7 is vertically movable on the guiding rails 16 and is provided with a cantilever arm 18 extending into the oil quenching chamber 2. Horizontally movably arranged on the arm 18 is a base member 19 of a cantilever. The cantilever comprises a supporting member 20 which in its turn is horizontally movably mounted on the base member 19.

The drive of the vertically and horizontally movable parts of the charging device is respectively effected by means of two chains 21 and 22 which pass over stationary sprocket wheels 23 and 24 respectively. The chains 21 have their ends connected to the lifting carriage 17 so that a movement of the chains 21 brings about a vertical movement of the lifting carriage 17. While the lower sprocket wheels 23 serve merely for reversing the chain 21, the upper sprocketwheels 23a are, according to FIG. 2, arranged on a common shaft 27 which through the intervention of a coupling 29 and a transmission a is connected to a motor 25 which is arranged outside the pressure container 3b for the oil quenching chamber 2.

Also the two lateral chains 22 for the horizontal movement of the cantilever comprising the base member 19 and the supporting member 20 are guided on stationary` sprocket wheels 24. i The chains 22 are guided in the front portion of the bil quenching chamber 2 over a vertically extending path so that in addition to a driven sprocket wheel 24a, three sprocket wheels 24 are required. The driven sprocket wheel 24a of each chain 22 is in its turn connected to a common shaft 28 which is adapted by means of a-coupling 29 and a transmission 26a to be coupled to a motor 26. The motor 26 together with the transmission 26a is located outside the quenching furnace as shown in F IG, 2.

FIG. 6 shows on an enlarged scale the arrangement of the sprocket wheels 24 and the path ofthe chains 22. FIG. 6 also shows that the two chains 22 laterally arranged in the oil quenching chamber 2 are interconnected by a pivot shaft 30 having connected thereto laterally two catching arms 31 and two guiding rollers 32. The guiding rollers 32 cooperate with control cams 33a and 33b in such a manner that the two arms 3l are adpated to be coupled to hooks 20a which are mounted on the supporting member 20 of the cantilever.

In order more clearly to show the course of movement of the catching arms 3l, four positions of an arm 3l are shownin FIG. 6. The position of the arm 31 illustrated by dot-dash lines shows the front position of the supporting member 20 occupied by the arm 3l in the transporting position in the hook 20a. During a driving movement of the sprocket wheel 24a in clockwise direction, the arm 31 moves in horizontal direction and in the direction toward the heating chamber 1. During this movement, the arm 31 is positively guided in horizontal position by its guiding roller 32 in the control cam 33a as illustrated in FIG. 6 by dashes and double points. In View of the movement of the arm 31 exclusively in horizontaldirection, the supporting member 20 is moved from its foremost position into that position which is shown in FIG. 3. ln this last mentioned position, the supporting member 20 is located in the heating chamber 1 as shown in FIG. 1.

A rearward movement of the supporting member 20 from the position of FIG. 3 to the position of FIG. 4 is effected by the return movement of chain 22. The supporting member 20 has reached the position shown in FIG. 4 as soon as the arm 31 occupies the dot-dash position. When it is desired to lower the supporting member 20 from this position together with a charging basket 10 into the oil container 4, as illustrated in FIG. 4, the arms 3l have to be moved out of the hooks 20a. Only thereafter is it possible to lower the lifting carriage 17 and thereby the supporting member 20 by means of the chains 21.

In order to obtain a disengagement of the arms 31 from the supporting member 20, the chains 22 are by a further turning of the sprocket wheel 24 moved in counterclockwise direction so that the guiding rollers 32 of the arms 3l move out of the control cam 33a. This position is shown in full lines in FIG. 6. As soon as the pivotable shaft 30 which carries the two arms 3l in the vicinity of the lowest point has arrived at the path of movement of chain 22 (see dash position in FIG` 6), the guiding rollers 32 cooperate with the second control cam 33b. This control cam 33h brings about that the arms 3l disengage the hooks 20a at the lower end thereof and subsequently are pivoted toward the front out of the range of movement of the charging device until they eventually occupy the position shown in FIG. 4. In this position, the lifting carriage 17 can be lowered while the hooks 20a pass by the arms 31. v

After the charge in the oil container 4 has cooled, the lifting carriage 17 is returned from its FIG. 5 position to its FIG. 4 position. Subsequently, the catching arms 31 are by turning the sprocket wheel 24a in clockwise direction again brought into hooks 20a so that after an exchange of the cooled off charge for a charge to b e heated, the charging device is ready to convey the new charging basket into the heating chamber 1 in the manner described above.

The individual phases of movement of chains 2l and 22 are brought about either by a corresponding programming of the motors 25 and 26 or by limit switches which additionally see to it that a movement of the lifting carriage 17 can be carried out only when the catching arms 3l occupy a position in which they are disengaged from the hooks 20a.

As will be evident from the above, the charging device according to the present invention has the important advantage that in the quenching furnace it is built up of simple mechanical structural elements which do not require special servicing. The charging device according to the invention is furthermore characterized in that the driving elements and control elements of the charging device are all located outside the quenching furnace so that they are not exposed to any particular stresses while being easily accessible. It will also be evident from the above that with the charging device according to the invention it is possible to lower the charges treated in the heating chamber, without the necessity of transloading them, into the oil bath so that any delays which are harmful for the hardness of the material will be eliminated. Furthermore, the charging device according to the present invention has a low overall height and requires relatively little space so that the pressure container of the oil quenching chamber does not have to meet special requirements.

lt is, of course, to be understood that the present invention is, by no means, limited to the particular showing in the drawings but also comprises any modifications within the scope of the appended claims.

What is claimed is:

1. ln a charging device for a furnace having a housing and a charging opening in a side wall of th housing; an oil quenching chamber in the housing adjacent said opening and a heating chamber in the housing on the opposite side of said oil quenching chamber from said opening, vertical guiding means fixed in the frame, a carriage movable along said guiding means, a horizontal support member fixed to said carriage and extending therefrom, a horizontal base member guided for horizontal movement on said support member, and a horizontal arm guided for movement on said base member, first chain means connected to said carriage for vertical movement thereof on said guiding means, second chain means connected to said support member for horizontal movement thereof, sprocket means inside said housing supporting said chain means, respective drive motors for said first and second chain means disposed outside said housing, and a drive connection extending from each said motor through a wall of said engagement with thehousing to the respective chain means.

2. A device according to claim 1 in which each chain means comprises a pair of chains in laterally spaced relation.

3. A device according to claim 1 in which one of the sprockets supporting each chain means is a driven sprocket, a shaft supporting each driven sprocket, and a drive connection connected to each of said shaft and extending sealingly through a wall of said housing and connected to a respective one of said motors.

4. A device according to claim l in which said first chain means includes at least one vertical reach connected to said carriage, said second chain means including at least one reach of which at least a portion is horizontal, said second chain means and said support member having thereon cooperating elements of connection means which are engageable and disengageable near one end of said horizontal portion of said one reach of said second chain means.

5. A device according to claim 4 in which 4the element of said connection means on said second chain means comprises at least one catching arm pivotally connected to said second chain means and having a member at one end drivingly engageable with the element of said connection means on said support member, and stationary cam means in said housing engaging said catching arm and operable in response to movement of said catching arm by said second chain means to effect said engagement and disengagement of said elements of connecting means.

6. A device according to claim 4 in which said one reach of said second chain means includes a vertical portion extending downwardly from the end of said horizontal portion nearest said opening, said element of connection means on said support member comprising a downwardly opening hook means on that end of the support member nearest said opening, said element of connection means on said second chain means comprising catching arm means pivotally connected to said second chain means and having one end part means extending toward said heating chamber and engageable with said hook means from below, and stationary cam means in said housing adjacent said one reach of said second chain means engaging and controlling said catching arm means, said cam means holding said end part means in said hook means during travel of said arm means horizontally and disengaging said end part means from said hook means during vertical travel of said arm means.

7. A device according to claim 6 in which said cam means causes movement of said end part means in the horizontal direction following disengagement thereof from said hook means to dispose said end part means out of the range of said support member to permit vertical movement of said support member into and out of a body of oil in said oil quenching chamber. 

1. In a charging device for a furnace having a housing and a charging opening in a side wall of th housing; an oil quenching chamber in the housing adjacent said opening and a heating chamber in the housing on the opposite side of said oil quenching chamber from said opening, vertical guiding means fixed in the frame, a carriage movable along said guiding means, a horizontal support member fixed to said carriage and extending therefrom, a horizontal base member guided for horizontal movement on said support member, and a horizontal arm guided for movement on said base member, first chain means connected to said carriage for vertical movement thereof on said guiding means, second chain means connected to said support member for horizontal movement thereof, sprocket means inside said housing supporting said chain means, respective drive motors for said first and second chain means disposed outside said housing, and a drive connection extending from each said motor through a wall of said housing to the respective chain means.
 2. A device according to claim 1 in which each chain means comprises a pair of chains in laterally spaced relation.
 3. A device according to claim 1 in which one of the sprockets supporting each chain means is a driven sprocket, a shaft supporting each driven sprocket, and a drive connection connected to each of said shaft and extending sealingly through a wall of said housing and connected to a respective one of said motors.
 4. A device according to claim 1 in which said first chain means includes at least one vertical reach connected to said carriage, said second chain means including at least one reach of which at least a portion is horizontal, said second chain means and said support member having thereon cooperating elements of connection means which are engageable and disengageable near one end of said horizontal portion of said one reach of said second chain means.
 5. A device according to claim 4 in which the element of said connection means on said second chain means comprises at least one catching arm pivotally connected to said second chain means and having a member at one end drivingly engageable with the element of said connection means on said support member, and stationary cam means in said housing engaging said catching arm and operable in response to movement of said catching arm by said second chain means to effect said engagement and disengagement of said elements of connecting means.
 6. A device according to claim 4 in which said one reach of said second chain means includes a vertical portion extending downwardly from the end of said horizontal portion nearest said opening, said element of connection means on said support member comprising a downwardly opening hook means on that end of the support member nearest said opening, said element of connection means on said second chain means comprising catching arm means pivotally connected to said second chain means and having one end part means extending toward said heating chamber and engageable with said hook means from below, and stationary cam means in said housing adjacent said one reach of said second chain means engaging and controlling said catching arm means, said cam meAns holding said end part means in said hook means during travel of said arm means horizontally and disengaging said end part means from said hook means during vertical travel of said arm means.
 7. A device according to claim 6 in which said cam means causes movement of said end part means in the horizontal direction following disengagement thereof from said hook means to dispose said end part means out of the range of said support member to permit vertical movement of said support member into and out of a body of oil in said oil quenching chamber. 